1. Field of the Invention
This invention relates to a liquid crystal display device provided with a driving circuit for generating a scanning signal and a data signal on the basis of image data supplied from outside.
2. Description of the Related Art
Since the liquid crystal display devices can be made small in size and thin, they are widely used as display devices for word processors, personal computers, television sets and the like.
The liquid crystal display device is used to be connected to separate driving circuits which generate data signals, scanning signals and the like.
Recently, in order to meet the requirement in which the display device should be further miniaturized, there has been proposed a liquid crystal display element having a liquid crystal display panel integrally formed with the above-mentioned driving circuit. The structure of the liquid crystal display panel of this type is shown in FIGS. 1 and 2.
The panel has two glass substrates 1 and 5. On one glass substrate 1 are formed pixel electrodes 2, thin film transistors 3 connected to the respective pixel electrodes 2, and gate lines G.sub.1 to G.sub.m and drain lines D.sub.1 to D.sub.n connected to the transistors 3. An aligning film 4 is formed on the pixel electrodes 2 and the transistors 3. On the other glass substrate 5 is formed a transparent common electrode 6 which is covered with an aligning film 7. Both glass substrates 1 and 5 are arranged to face each other and are fixed by means of a seal member 8. Liquid crystal 9 is filled in the space defined between both glass substrates 1 and 5 through a hole 10. After filling the liquid crystal 9 the hole 10 is sealed by a seal member 11 so that the liquid crystal 9 is kept in the space between the opposed glass substrates 1 and 5. Each pixel is constituted by one of the pixel electrodes 2, the portion of the common electrode 6 which faces the same and the portion of the liquid crystal 9 which is disposed therebetween in such a manner that a plurality of pixels similarly formed are arranged in a matrix form.
A driving circuit comprises drain line driving circuits 12 for supplying data signals to the pixel electrodes 2 and gate line driving circuits 13 for controlling the thin film transistors associated with the respective pixel electrodes 2 in response to image data to be displayed. Each of the drain line driving circuits 12 and the gate line driving circuits 13 comprises an integrated circuit including a plurality of thin film transistors directly formed on a substrate. The driving circuits 12 and 13 are arranged on the peripheral portions of the glass substrate 1 disposed outside of the seal member 8. The output terminals of the driving circuits 12 and 13 are connected to the drain lines D.sub.1 to D.sub.n and the gate lines G.sub.1 to G.sub.m, respectively. The drain line driving circuits 12 and the gate line driving circuits 13 are connected to signal lines 14 which supply control signals and image data signals and are also connected to a terminal 15 provided on the glass substrate 1.
Image data signal and control signals such as clock signals are input to the liquid crystal display device of the active matrix type. The gate signals produced by the gate line driving circuits 13 are supplied to the gate lines G.sub.1 to G.sub.m in succession and each gate signal selects the corresponding one of the gate lines G.sub.1 to G.sub.m. The data signals produced by the drain line driving circuits 13 in synchronism therewith at the time interval of the selection of the gate lines are supplied to the drain lines D.sub.1 to D.sub.n.
The transistors 3, which are connected to one gate line selected by the gate signal, turn on. Each data signal is supplied to the pixel electrode through the turned-on transistors 3. An electric field is produced between the pixel electrode 2 to which the gate signal is supplied and the common electrode 6 to which a common signal is supplied. The liquid crystal 9 disposed between both electrodes 2 and 6 is made active by means of the electric field so as to display image data.
Since the driving circuit is integrally formed with the liquid crystal display panel in the liquid crystal display device as explained above, the display device is made small in size. No process is required to connect the driving circuit to the panel by means of lead wires or the like, leading to a simplified manufacturing process.
However, the above-mentioned driving circuit is mounted on the portions of the liquid crystal panel which is disposed outside of the seal member 8. Thus, the outer peripheral portions of the substrate require a large area. In other words, the liquid crystal display panel has a large peripheral area which is not associated with the image display and this peripheral are surrounds the display area in which the pixels are arranged in a matrix form and which is effective for image display. Accordingly, this liquid crystal display device has a problem in that it requires a large area.
The object of this invention is to provide a small sized liquid crystal display device which overcomes the problems as mentioned above.